// 可见性
.visible{visibility: visible;}
.invisible{visibility: hidden;}

.opacity{
  &-0{opacity: 0;}
  &-10{opacity: 0.1;}
  &-20{opacity: 0.2;}
  &-30{opacity: 0.3;}
  &-40{opacity: 0.4;}
  &-50{opacity: 0.5;}
  &-60{opacity: 0.6;}
  &-70{opacity: 0.7;}
  &-80{opacity: 0.8;}
  &-90{opacity: 0.9;}
  &-100{opacity: 1;}
}